sprink58

I found out that , unfortunately for me, my Hero 960 has no remote control apps available. I guess i will have to stop and put reading glasses on in order to read this thing LOL

Crude Intentions

Or just upgrade to the hero 3 black edition ��

sprink58

I am running Mirage Plus 23" pitch with 1.5 ratio Bravo I drives.

I took a guess on the props...and I guess I got lucky. After a few hours of break in I ran it out briefly to get a feel for what I have. I have seen on two occasions 75 MPH GPS at 5600 RPM. The boat cruises at 34~35 GPS at 2200 RPM

[IMG][/IMG]

....3000 RPM gives me about 44 GPS. In looking at the picture above one thing comes to mind very quickly....TORQUE!! These Vortec Roller cam engines are already making close to 400 ft lbs at 2200 RPM ! That mightr seem "Ho hum" to a lot of you younger guys but to an "Old School" guy like me it's mind boggling ! My old '86 272 LS with twin 320 EFI's would spin twin 23" Mercruiser Cleavers between 3500-3700 RPM to carry it 35 MPH. The two boats weigh with in 200 lbs of each other with a center line length difference of 18"!! That speaks volumes also in how far we have come in prop efficiency...not to mention engine efficiency. The Vortec heads and Roller Cams changed the game with SBC's. Back when this boat was new the only way you got those numbers were with "massaged" BBC's and with that you paid a weight penalty ...big time. To think that this same 255 was available with twin 420 Horsepower 454 TRS drives is incredible. Imagine the weight difference between that package and the Twin SBC/Bravo I package now is nuts...no wonder these 255's have so much freeboard built in...with out it twin BBC/TRS's would have the rub rail 2" above the water at the transom!! This is what it looks like at rest as equiped.

[IMG][/IMG]

Only about a third of the hull is below the waterline at the transom.

The boat gets on a plane very quickly...surprisingly so for a twin engine deep v.

It appears from the BAM prop slip calculator that I am running right at a 7% prop slip which I think is phenomenal for this combination!!!

I had it out Sunday and was able to make a few short runs into the low 70's. When I tried to run it up later in the day...suddenly neither engine would spin past 3100~3200 RPM....just about 45. I backed off and thought about it and think I may have a fuel starvation problem.

I will dump both water separators and see what is in them. I may also have a partially plugged pick up tube for each engine. I don't think my boat has an anti siphon check valve ( 1979 vintage) but I will take a closer look. All fuel lines are new.

PS...I do have Anti Siphon hose barbs at my tank so I will change them for sure...there about $15 ea at West Marine so that's a no brainer.

One of the things I am noticing with both props turning clockwise is that this boat is a pain in the a$$ to dock due to prop walk...the stern wants to move starboard with both drives in forward...it's actually easier to handle just using one. I also notice at high speeds...50 MPH plus the handling gets a little twitchy and when I do catch air the stern automatically rotates to the starboard...very scary $hit!!! This happened Sunday flying off the top of a 4 footer around 60 and I nearly filled my shorts as I came down for a landing!! Got to get a new controller so I can run that port drive CCW.

The power to weight ratio with this combination has created a very strong performer. My challenge now is to calibrate all of the controls to be able to effectively handle all that I have. I am taking a very sober approach to this because I have seen a few guys hurt over the years in much less capable boats simply because they didn't recognize there own limitation or those of their equipment. When you are running in the open ocean at speeds in excess of 60-65 MPH...things can go south very quickly if you aren't aware of your surroundings and not focused on what you are doing.

It is exhilarating though to run this old 'bird at speeds most boats from the era (1970's) would not achieve in any thing less than race trim. As much as it puts a grin on my face ...some how I think this old 255 is sporting a grin as well...as if to say.."See...I told you !!!"

rabbit

Very cool post. Sounds like you are having a blast...alas I am still in the trenches! Soon, I hope to be out of the work stage and in the fun runs.

Crude Intentions

Very good numbers John. My guess would be fuel as well. For both to do same thing at same time.

masi242

Well at that speed you may need these to help out any passengers[ATTACH=CONFIG]508583[/ATTACH][ATTACH=CONFIG]508584[/ATTACH].

sprink58

Hard to find those....especially here where there aren't many old Formulas.

masi242

John, they are yours if you want them they are missing a couple of the posts where they attach to the gunnel, pm me your address, I just need to find a box for them.

mark

Mr Maine

Wow thats a nice offer

masi242

With the new bolsters I have I won`t be using them, just a small grab bar on the back of the seat.